Styela gibbsii (Stimpson, 1864)

Common name(s): Brown tunicate, peanut sea squirt, sea peanut

Synonyms: Cynthia gibbsii Styela gibbsi
Phylum Chordata 
Subphylum Urochordata 
Order Stolidobranchia 
Family Styelidae 
Styela gibbsi, about 3 cm tall, found subtidally near Rosario
(Photo by:  Dave Cowles, August 2009)
Description:   This solitary tunicate has an opaque tunic which is wrinkled but has no spinelike or harilike projections.  Both the buccal and the atrial siphons are near each other at the upper end.  The tunic narrows at the attachment point at the base but is not extended into a long stalk.  The body is an upright, elongated cylinder with conspicuous lengthwise wrinkles but not lumpy.  May also have transverse wrinkles in a contracted animal.  Brown or brownish red.  May be a slight orange tinge on siphons when open.  Up to 6 cm tall (usually less than 4 cm), 0.5 to 2 cm wide.

How to Distinguish from Similar Species: Styela montereyensis and S. clava have a much more elongated basal stalk. S. plicata is similar in form to S. gibbsi but has large lumps rather than longitudinal wrinkles. S. truncata is up to 3 cm tall and has a yellowish to reddish brown tunic which is smooth unless the animal is contracted. P haustor has lumps as well as wrinkles, red siphon tips, and is often covered with debris.

Geographical Range:   Alaska to California

Depth Range:  Rare intertidally.  Common subtidally

Habitat:  Pilings, rocky substrates, stones, or shells, especially often attached to Trichotropis cancellata shells.  May aggregate together or be mixed with tunicates of other species.

Biology/Natural History:   This species does not brood its larvae.

May be parasitized by the parasitic barnacle Peltogaster sp or by the parasitic copepods Scolecimorpha huntsmanni and Enterocola laticeps.  The commensal pea crabs Fabia subquadrata or Pinnixa faba may live in the atrial cavity.



Dichotomous Keys:
  Carlton, 2007
  Flora and Fairbanks, 1966
  Kozloff, 1987, 1996

General References:
  Johnson and Snook, 1955
  Kozloff, 1993
  Lamb and Hanby, 2005
  MacGinitie and MacGinitie, 1949

Scientific Articles:

Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors:

Authors and Editors of Page:
Dave Cowles (2009):  Created original page
CSS coding for page developed by Jonathan Cowles (2007)